Concrete piles that are driven to the ground serve to provide foundation support to structures. Weight of the structure is distributed by the piles in order to reduce the risk of structural failure. Precast piles that are reinforced with rebar are commonly prestressed to enhance its tensile stress resistance for reducing cracking. However, the ultimate strength in axial compression is inversely proportional to the level of prestressing such that when the level of prestressing increases, the ultimate strength in axial compression decreases.
As a single long slender concrete pile is prone to breakage during lifting, therefore such long concrete pile is often installed by dividing the pile into multiple sections and stacking them atop one another. Moreover, by employing multiple joined pile sections, long piles can be driven. The pile sections are joined end-to-end by pile splices or connectors. An example of such pile connector is known in U.S. Pat. No. 4,157,230, whereby a nut is constructed within the joining ends of the two pile sections for a threaded bolt to be fastened to the nuts. The nut is provided with an annular groove having radially directed locking notches in the bottom. A locking disk is inserted into the groove. The disk has resilient locking tongues with radial edges which are directed against the unscrewing direction and which engage with the notches in the nut.
U.S. Pat. No. 2,698,519 discloses another concrete pile connector that is utilized to join two sectional cast concrete piles which have longitudinal metal reinforcing rods therein. The connector has a first annular band-like metal ring secured to and surrounding certain reinforcing rods at an end portion of a first pile section. The outer surface of the ring conforms to the contour of the outer surface of the end portion of the first pile section. A second annular band-like metal ring with the same design and configuration as the first annular band-like metal ring is secured to the end portion of a second pile section. Both rings are connected by having the two end portions of a tubular metal sleeve that encompasses the abutting ends of the first and second pile sections to be respectively welded to the first and second ring.
The pile connectors from the prior arts mentioned above are used for precast concrete pile but is not adapted to be incorporated into prestressed spun piles manufacturing as it obstruct the prestressing jack equipment, and the non-symmetry will induced irregular vibrations during the pile spinning process. This present invention is specially adapted for the fabrication of spun piles without having to additionally modify the existing spun pile mould or the prestressing equipment. The interlocking profile of the present invention can be incorporated and replaced into the existing annular steel rings for spun pile joints. This present invention introduces a pair of complementary pile connectors that not only contributes to the simple and easy joining of concrete pile sections but also ensures that the strength of the connectors is greater than the ultimate bending, compressive and tensile capacity of the intact concrete section of the pile.